Error correcting method, disk medium, disk recording method and disk reproducing method

Abstract

The disk medium 200 of the present invention includes a sector group 3 including a plurality of positionally continuous sectors 2 in which address information including at least address data and parity data is dispersedly provided in the plurality of sectors of the sector group in a prescribed unit. The address information includes an information sequence described by a combination of at least “0”, “1” and an identification mark 4 , the identification mark is provided at the head of the sector group, the address data includes data bits, and the parity data includes parity bits. With this structure, it is possible to realize small address redundancy and high reliability of address reproduction.

1 . An error correcting scheme, wherein when an error correcting code includes twenty data bits, seven parity bits as a burst error correction code for the data bits and five parity bits as a random error correction code for the data bits, the number of burst error correction bits of the burst error correction code is three and the number of random error correction bits of the random error correction code is one, a combination of a syndrome of the burst error correction code and a syndrome of the random error correction code is unique to each of 1-bit errors, 2-bit errors and 3-bit burst error and error correction is performed based on the syndrome of the burst error correction code and the syndrome of the random error correction code.  
     
     
         2 . A disk medium comprising a sector group including a plurality of positionally continuous sectors in which address information including at least address data and parity data is dispersedly provided in the plurality of sectors of the sector group in a prescribed unit, the address information including an information sequence described by a combination of at least 0, land an identification mark, the identification mark being provided at the head of the sector group, the address data including data bits, and the parity data including parity bits.  
     
     
         3 . A disk medium according to  claim 1 , wherein a length of the sector group is shorter than one track length.  
     
     
         4 . A disk medium according to claims  2  or  3 , wherein an integral number of the sector groups are set so as to be a unit of information to be recorded or reproduced.  
     
     
         5 . A disk medium according to any one of claims  2 - 4 , wherein the address information is dispersedly provided in the plurality of sectors of the sector group by one code alphabet.  
     
     
         6 . A disk medium according to any one of claims  2 - 5 , wherein in the address information, the address data is positioned so as to follow the identification mark and the address data includes a LSB.  
     
     
         7 . A disk medium according to any one of claims  2 - 5 , wherein in the address information, the parity data is positioned so as to follow the identification mark, the address data is positioned after the parity data, and the address data includes the LSB.  
     
     
         8 . A disk medium according to any one of claims  2 - 7 , wherein the disk medium has a capacity of 235 bytes or lower, one sector includes 211 byte-data, the sector group includes thirty two sectors, and the address information is configured so as to include a 1-bit identification mark, 19-bit address data, 7-bit parity data of the burst error correction code for the address data, and 5-bit parity data of the random error correction code for the address data.  
     
     
         9 . A disk medium according to any one of claims  2 - 7 , wherein the disk medium has a capacity of 236 bytes or lower, one sector includes 211 byte-data, the sector group includes thirty two sectors, the address information is configured so as to include a 1-bit identification mark, 19-bit address data, 7-bit parity data of the burst error correction code for the address data, and 5-bit parity data of the random error correction code for the address data, and the 1-bit identification mark can be selected from two types of identification marks.  
     
     
         10 . A disk reproducing method, wherein in the disk medium according to any one of claims  3 - 9 , after reproducing address information of a prescribed and specific sector group, a track jump over one track is performed so as to reproduce the address information of the prescribed and specific sector group from the lead thereof.  
     
     
         11 . A disk reproducing method, wherein in the disk medium according to any one of claims  2 - 9 , detection of the identification mark starts acquisition of the address information.  
     
     
         12 . A disk recording method, wherein in the disk medium according to any one of claims  4 - 9 , detection of the identification mark starts a data recording operation or data reproducing operation.  
     
     
         13 . A disk reproducing method, wherein in the disk medium according to any one of claims  4 - 9 , detection of the identification mark starts a data recording operation or data reproduction operation.  
     
     
         14 . A disk recording method, wherein in the disk medium according to any one of claims  2 - 9 , error detection or error correction is performed on reproduced address information and a recording/reproducing operation is performed on the sector group represented by the address information based on a result of the error detection or error correction.  
     
     
         15 . A disk reproducing method, wherein in the disk medium according to any one of claims  2 - 9 , error detection or error correction is performed on reproduced address information and a recording/reproducing operation is performed on the sector group represented by the address information based on a result of the error detection or error correction.  
     
     
         16 . A disk reproducing method, wherein in the disk medium according to any one of claims  2 - 9 , when it is detected that a size of an envelope of a reproduced signal representing bits in reproduced address information are not in a prescribed range or it is detected, based on the reproduced signal representing the bits in the address information, that relative positions of a head and a track are not in a prescribed range, reproduced data bits corresponding to the bits in the reproduced address information can be used as erasure bits so as to perform an erasure correction.  
     
     
         17 . A disk recording method, wherein in the disk medium according to any one of claims  2 - 9 , burst error correction is performed on reproduced data of the address information.  
     
     
         18 . A disk reproducing method, wherein in the disk medium according to any one of claims  2 - 9 , burst error correction is performed on reproduced data of the address information.  
     
     
         19 . A disk recording method, wherein in the disk medium according to any one of claims  2 - 9 , random error correction is performed on reproduced data of the address information.  
     
     
         20 . A disk reproducing method, wherein in the disk medium according to any one of claims  2 - 9 , random error correction is performed on reproduced data of the address information.  
     
     
         21 . A disk recording method, wherein in the disk medium according to any one of claims  2 - 9 , burst error correction or random error correction is performed on reproduced data of the address information.  
     
     
         22 . A disk reproducing method, wherein in the disk medium according to any one of claims  2 - 9 , burst error correction or random error correction is performed on reproduced data of the address information.  
     
     
         23 . A disk recording method, wherein in the disk medium according to any one of claims  6  or  7 , a part of the address information is reproduced so as to detect that a sector group being reproduced is not an expected sector group.  
     
     
         24 . A disk reproducing method, wherein in the disk medium according to any one of claims  6  or  7 , a part of the address information is reproduced so as to detect that a sector group being reproduced is not an expected sector group.